There is a growing need for a machine press which presses a work object to operate safely. For example, there is a growing need for a technique to stop operation of the machine press when it detects that part of a worker's body has entered an area in which an action part of the machine press operates (dangerous area).
FIGS. 1A and 1B each show an example of an action part of an electrical machine press according to Patent Literature 1. FIG. 1A is an elevation view of the action part of the electrical machine press. Moreover, FIG. 1B is a left side view of the action part of the electrical machine press.
An upper mold 7 is mounted under an upper slide 3, while a lower mold 9 is mounted on a lower slide 5. Hereafter, the upper slide 3 and the lower slide 5 are referred to as the upper and lower slides or only the slides. A work object W is disposed between the upper mold 7 and the lower mold 9. Then, a distance between the upper mold 7 and the lower mold 9 is decreased. As a result, pressure is applied to the work object W and the work object W is processed. The upper slide 3, the lower slide 5, the upper mold 7, and the lower mold 9 are components for processing the work object W, all of which correspond to the action part.
For example, the worker causes a hand to enter between the upper and lower slides from a front plane in FIG. 1A, that is, from a right side in FIG. 1B in order to replace the work object or determine a position of the work object. A region in which a hand is likely to be caught (dangerous area) is a position sandwiched between the upper mold 7 and the lower mold 9.
In a conventional machine press, a worker prevents a hand from being caught in the machine through manually cutting off power when a work for replacing the work object or determining the position of the work object is performed. Moreover, a machine press according to Patent Literature 2 prevents a hand of a worker from being caught, in the machine by automatically cutting off power based on detection by an entry detection sensor, an area sensor, or the like that part or the whole of the worker's body has entered a dangerous area.